SD DVD iso's play fine, very good quality, MPEG2 from encoded home video works well. SD H.264 stored on server from Samsung camcorder stutter from the word go, via transcoding I get about 10 seconds before stutter sets in and then unwatchable.

Edited to add that if I pause at the beginning of a transcoding session for about 30 seconds the file is completely watchable that time and then for the remainder of the time if I decide to view the same file again. When I watch it again it plays fine without having to delay. Move to a new file and a healthy dollop of pause is needed. Transcoding buffer never drains.